// 将下面代码用promise方式实现
setTimeout(function() {
    var a = 'hello'
    setTimeout(function() {
        var b = 'lagou'
        setTimeout(function() {
            var c = 'I ❤️ U'
            console.log(a + b + c)
        }, 10)
    }, 10)
}, 10)

// promise方式实现
Promise.resolve('hello')
    .then(value=> {return value + 'lagou'})
    .then(value => console.log(value + 'I ❤️ U'))

